Wednesday, November 14, 2012
Elephants are actually helping to keep the lights on at the Munich Zoo. The zoo's resident Indian elephants are providing 'Elephant Energy' by creating power generated from their dung. This is achieved by harnessing what the Munich Zoo is referring to as "poo power" -- energy stored in animal waste -- which can be converted into a fuel known as "biogas."
How It Works…
The zoo has built three large containers, each capable of holding about 100 cubic meters of animal waste --which is approximately a week's worth of dung collected from all the vegetarian animals in the zoo. The dung is then mixed with warm water and the bacteria in the dung is left to decompose in an oxygen-free environment for 30 days. The resulting biogas, mainly comprised of methane and carbon dioxide, rises naturally through vents in the ceiling to a corrugated hut on the roof where it's collected in a "big balloon" which resembles a small Zepplin. The biogas is then fed into a gas-powered engine that's used to generate electricity.
"When you turn the biogas into electricity, it creates heat which we also store," Munich Zoo park supervisor Dominik Forster told CNN. "This is then used to warm the gorilla enclosure, -- but it could be used to heat about 25 homes," he added.
Apparently, dung alone does not produce all that much energy relative to its size, and by the time the food has been digested by the animal, a lot of the energy in it has been used up or burped out. However, using animal waste to create electricity, heat or fertilizer is important in helping change our mindset from dependence on one source of energy to many different complementary sources.
By Nick Glass and George Webster, CNN